Optical module and optical transmitting apparatus installing a number of optical modules

Abstract

An optical module installed within an optical transmitter apparatus is disclosed. The optical module provides an electrically insulating carrier, a semiconductor element, and a capacitor. The carrier provides a ground pattern and a bias pad. The ground pattern mounts the capacitor and the semiconductor element thereon. The bias pad is electrically isolated from the ground pattern thereby forming a parasitic capacitor against the ground pattern. The optical module further includes at least two bonding wires among a first bonding wire connecting the semiconductor element with the bias pad, a second bonding wire connecting the bias pad with the capacitor, and an additional bonding wire connecting the capacitor with the semiconductor element. The semiconductor element is supplied with a bias current through the at least two bonding wires.

What is claimed is: 
     
       1. An optical module that generates a modulated optical beam, comprising:
 an electrically insulating carrier that provides a ground pattern and a bias pad on a top surface thereof, the bias pad being electrically isolated from the ground pattern thereby forming a parasitic capacitor against the ground pattern; 
 a semiconductor element mounted on the ground pattern, the semiconductor element generating the modulated optical beam by being supplied with a bias current; 
 a capacitor mounted on the ground pattern; and 
 at least two bonding wires among a first bonding wire connecting the semiconductor element with the bias pad, a second bonding wire connecting the bias pad with the capacitor, and an additional bonding wire connecting the capacitor with the semiconductor element, 
 wherein the capacitor and the parasitic capacitor are operable in complementary with respect to frequencies, and 
 wherein the bias current is supplied to the semiconductor element from the capacitor through the at least two bonding wires. 
 
     
     
       2. The optical module of  claim 1 , wherein the bias current is supplied through the first bonding wire and the second bonding wire by removing the additional bonding wire. 
     
     
       3. The optical module of  claim 1 , wherein the bias current is supplied through the additional bonding wire by removing the first bonding wire but leaving the second bonding wire. 
     
     
       4. The optical module of  claim 1 , wherein the bias current is supplied through the additional bonding wire by removing the second bonding wire but leaving the first bonding wire. 
     
     
       5. The optical module of  claim 1 , wherein the capacitor has a type of die-capacitor having a top electrode and a back electrode, the top electrode being wire-bonded with the second bonding wire and the additional bonding wire, the back electrode being in contact with the ground pattern. 
     
     
       6. The optical module of  claim 1 , wherein the semiconductor element provides a back metal connected to the ground pattern and a pad in a top surface thereof, the pad being wire bonded with the bias pad with the first bonding wire and with the capacitor with the additional bonding wire. 
     
     
       7. The optical module of  claim 1 , wherein the carrier further provides a co-planar line with a signal line surrounded by the ground pattern, the signal line being wire-bonded to the semiconductor element through a bonding wire. 
     
     
       8. The optical module of  claim 7 , wherein the carrier further provides a termination pad that is wire-bonded to the semiconductor element with a bonding wire, the termination pad being grounded through a terminator. 
     
     
       9. An optical transmitter apparatus that generates a multiplexed optical beam, comprising:
 a number of optical modules each including,
 an electrically insulating carrier that provides a ground pattern and a bias pad on a top surface thereof, the bias pad being electrically isolated from the ground pattern thereby forming a parasitic capacitor against the ground pattern, 
 a semiconductor element mounted on the ground pattern, the semiconductor element generating a modulated optical beam supplied with a bias current thereto, 
 a capacitor mounted on the ground pattern, and 
 at least two bonding wires among a first bonding wire connecting the semiconductor element with the bias pad, a second bonding wire connecting the bias pad with the capacitor, and an additional bonding wire connecting the capacitor with the semiconductor element, 
 wherein the bias current is supplied to the semiconductor element from the capacitor through the at least two bonding wires; and 
 
 an optical multiplexing system that multiplexes the modulated optical beams generated in the optical modules into the multiplexed optical beam, 
 wherein the number of the optical modules is four (4), and 
 wherein the optical multiplexing system includes four first lenses, a beam splitter, four second lenses, two wavelength selective filters, and a polarization beam combiner, the first lenses concentrating the modulated beams output from the optical modules into four concentrated beams, the beam splitter splitting the four concentrated beams into four monitored beams and four signal beams, the second lenses converting the four signal beams into four collimated beams, the wavelength selective filters multiplexing two of the four signal beams and generating two multiplexed beams, the polarization beam combiner multiplexing the two multiplexed beams depending on polarizations thereof into the multiplexed optical beam output from the optical transmitter apparatus.